On the left in the photo is a new filter for our AC/furnace; on the right, one about 60-75 days old including two weeks of wildfires. This is, of course, used inside the house, so everything here has come inside though we've had the doors and closed almost all of the time for the past couple of weeks.
These are MERV 13 filters (which our landlord is paying for! Thanks!) Two technicians from Blake's said that a filter of this high value is suitable for our fairly modern HVAC. These are what's planned for use at Lincoln40. When they get this black and clogged up they also start to whistle a bit in the holder as air is trying to go around them, which at least raises energy costs.











